3,3,3-Trifluoro-1-chloropropene, also known as 1-chloro-3,3,3-trifluoropropene (HCFO-1233zd), exists in the form of two isomers: the cis isomer, namely Z-3,3,3-trifluoro-1-chloropropene (HCFO-1233zdZ), and the trans isomer, namely E-3,3,3-trifluoro-1-chloropropene (HCFO-1233zdE). They have different boiling points: 18.5° C. for the trans compound and 39.5° C. for the cis compound, respectively.
Fluids based on E-3,3,3-trifluoro-1-chloropropene (HCFO-1233zdE) have found numerous applications in varied industrial fields, especially as heat-transfer fluids, propellants, foaming agents, swelling agents, gaseous dielectrics, polymerization media or monomers, support fluids, abrasives, drying agents and fluids for power production units.
The manufacture of HCFO-1233zdE is accompanied by a multitude of by-products, having a boiling point close to HCFO-1233zdE. This leads to quite complex and expensive purification steps. The difficulties encountered during the purification of HCFO-1233zdE generally entail a consequent loss of the desired product. Furthermore, the by-products may form azeotropic compositions with HCFO-1233zdE, making separation by simple distillation very difficult or even impossible.
U.S. Pat. No. 6,013,846 describes an azeotropic composition of HCFO-1233zd and hydrogen fluoride (HF). The document does not mention the isomeric form of HCFO-1233zd.
U.S. Pat. No. 6,328,907 describes an azeotropic composition of 1,1,1,3,3-pentafluoropropane (HFC-245fa) and HF.
U.S. Pat. No. 8,378,158 describes a quasi-azeotropic composition of HCFO-1233zdZ and HF.
U.S. Pat. No. 7,423,188 describes an azeotropic composition of E-1,3,3,3-tetrafluoropropene (HFO-1234zeE) and HF.
WO 2008/002500 describes an azeotropic composition of Z-1,3,3,3-tetrafluoropropene (HFO-1234zeZ) and HF.
U.S. Pat. No. 7,183,448 describes an azeotropic composition of HFC-245fa and HCFO-1233zd. It is pointed out in the document that the azeotrope is obtained with the trans isomer of HCFO-1233zd.
U.S. Pat. No. 8,075,797 describes a quasi-azeotropic composition of HF, HFC-245fa and HCFO-1233zd. It is pointed out in the document that the quasi-azeotrope is obtained with the—trans isomer of HCFO-1233zd.
There is still a need to provide other azeotropic compositions and especially azeotropic compositions based on compounds that can participate in the manufacture of HCFO-1233zdE. However, in general, azeotropes are difficult to predict.